Scroll-Type Fluid Machiner

ABSTRACT

A scroll-type fluid machine is configured so that the scroll-type fluid machine has compact, lightweight, and long life characteristics obtained by mounting, without increasing the diameter of the barrel, a bearing having a higher load capacity and so that a degradation in the performance due to a pressure loss during a high flow-rate operation is minimized by providing the gas flow path in the center plate with a sufficient cross-sectional area. A scroll-type fluid machine is provided with: a first housing which contains a scroll mechanism; a second housing which contains an electric motor; and a center plate which is disposed between both the housings, which contains a motion conversion mechanism for converting rotational motion to orbiting motion, which has mounted thereto a rotation prevention mechanism for preventing the rotation of a movable scroll, and which holds the bearing for supporting the main shaft. At least a part of the fluid path, which connects the insides of the first and second housings through the portion at which the center plate is disposed, is configured to connect an axial recess and a radial recess which are formed in the center plate, the axial recess facing the inside of the second housing and extending in the axial direction, the radial recess being located closer to the first housing than the bearing and extending in the radial direction.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a scroll-type fluid machine, such as a scroll-type electric compressor for air-conditioning and a scroll-type expander which is loaded with an electric generator used for recovering exhaust heat from vehicles and boilers.

BACKGROUND ART OF THE INVENTION

Known is an electric compressor of which electric motor and scroll-type compression mechanism are placed in the same axis. Such a compressor comprises a housing to house a pair of scroll bodies, another housing to house an electric motor and a center plate provided with mechanism component parts which convert a rotation into a swing, as disclosed in patent document 1 and 2. In such a compressor, after refrigerant is sucked from a suction port provided on a housing to house the electric motor, it passes through a void of the electric motor, and then through a void of a bearing held by the center plate or a void of an outer periphery of a cylindrical section which holds the bearing, so as to be taken into the scroll bodies and discharged from a discharge port of a housing to house the pair of scroll bodies.

On the other hand, in the expander which is loaded with the electric generator, the suction port and the discharge port are reversed so that refrigerant flows in a direction opposite to the above-described case of compressor. In other words, after refrigerant is sucked from a suction port provided on a housing to house a pair of scroll bodies and is taken into the scroll bodies, it passes through a void of a bearing held by the center plate or a void of an outer periphery of a cylindrical section which holds the bearing, and then through a void of the electric generator, so as to be discharged from a discharge port of a housing to house the electric generator.

PRIOR ART DOCUMENTS Prior Documents

Patent document 1: JP2008-232057-A

Patent document 2: JP2008-303819-A

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

In the process of research and development aiming to reliability improvement and reduction in size and weight of scroll-type fluid machines, a main shaft bearing was required to have a great load capacity without scaling up a body diameter of a compressor. However, it is difficult to form a void as a main gas flow path because the outer diameter of a cylindrical section holding the bearing becomes almost equal to the inner diameter of a coupling section of a movable scroll body when the outer diameter of the bearing is enlarged in order to increase the load capacity of the bearing without changing the inner diameter which may affect on another component part. Furthermore, it is difficult that performance deterioration from pressure loss during high flow-rate operation is prevented only by the void of the bearing.

Accordingly, an object of the present invention is to provide a scroll-type fluid machine which can achieve a long life and a reduction in size and weight while a bearing with greater load capacity is incorporated without enlarging the body diameter and which can prevent the performance deterioration from pressure loss during high flow-rate operation by ensuring the section area of the gas flow path of the center plate.

Means for Solving the Problems

To achieve the above-described object, a scroll-type fluid machine according to the present invention is a scroll-type fluid machine comprising a first housing which houses a scroll mechanism made of a fixed scroll and a movable scroll, a second housing which houses an electric motor to rotate a main shaft, and a center plate, which is interposed between the housings, which has a motion conversion mechanism to convert a rotation motion of the main shaft to a swing motion of the movable scroll, which is provided with a rotation preventing mechanism for the movable scroll, and which holds a bearing to hold the main shaft, and a fluid path which communicates an inside of the second housing and an inside of the first housing through an installation part of the center plate, characterized in that at least a part of the fluid path is formed by connecting an axial recessed portion and a radial recessed portion, which are formed in the center plate, the axial recessed portion facing the inside of the second housing and extending in an axial direction, the radial recessed portion being located closer to the first housing than the bearing and extending in a radial direction.

In the scroll-type fluid machine, at least a part of the fluid path, which connects the inside of the first housing and the inside of the second housing through the center plate, is formed by connecting the axial recessed portion and the radial recessed portion which are formed in the center plate, so as to sufficiently ensure the section area of the gas flow path and to prevent the performance from deteriorating by pressure loss during a high flow-rate operation. Further, the fluid path is formed by connecting the axial recessed portion extending axially along the main shaft and the radial recessed portion extending radially, so that the gas flow path can be formed by a simple processing.

In the scroll-type fluid machine of the present invention, it is preferable that a plurality of the axial recessed portions are formed along a circumferential direction. Such axial recessed portions make it easy to ensure the section area of the fluid path even if a bearing with relatively high load capacity is incorporated.

Furthermore, it is preferable that a part of an inner surface of the axial recessed portion is formed to be a surface extending in a shape tapered toward the inside of the second housing. The axial recessed portion is formed in such a shape, so that the strength of the center plate is maintained and the processing is simplified.

In the scroll-type fluid machine of the present invention, it is preferable that the radial recessed portion is formed to be a ring-shaped recess extending in a circumferential direction. The radial recessed portion is formed in such a shape, so that the processing is simplified.

It is preferable that a part of an inner surface of the radial recessed portion is formed to be a surface extending in a shape tapered toward the inside of the second housing from the inside of the first housing. The radial recessed portion is formed in such a shape, so that the strength of the center plate is maintained and the processing is simplified.

In the scroll-type fluid machine of the present invention, it is preferable that the axial recessed portion is provided at a time of producing a material for the center plate. The axial recessed portion is provided at the same time of producing the material for the center plate, so that the production process of the center plate can be simplified. Further, it is preferable that the material for the center plate is produced by casting and the axial recessed portion is formed with a die. Furthermore, it is possible that the radial recessed portion is formed with a core mold. Such a production process is employed, so that the center plate can be produced further efficiently.

In addition, it is possible that the radial recessed portion is formed by machining. The machining can be easily performed especially in a case where the radial recessed portion is formed into a ring-shaped recess extending in a circumferential direction.

In the scroll-type fluid machine, it is possible that the center plate is formed integrally with either the first housing or the second housing. When the center plate is formed to be unified with the first housing or the second housing, the number of component parts can be reduced and the assembly process of the scroll-type fluid machine can be simplified.

The scroll-type fluid machine of the present invention can be constructed as a compressor or an expander. Namely, in the scroll-type fluid machine of the present invention, function as a compressor or an expander can be shown as depending on the rotational direction of the main shaft. Specifically when it is constructed as a compressor, it is preferable that a discharge valve is provided.

The scroll-type fluid machine according to the present invention is suitably used as a fluid machine loaded in a vehicle. Because fluid machines loaded in vehicles are strongly required to have a small size and a light weight, technical features of the scroll-type fluid machine of the present invention can be brought out effectively therein.

Effect According to the Invention

A scroll-type fluid machine according to the present invention makes it possible that the section area of the fluid path is sufficiently ensured by a simple processing and that the performance deterioration caused by a pressure loss during high flow-rate operation is efficiently prevented. As a result, it is not necessary for the body diameter to enlarge even when a bearing having higher load capacity is incorporated, so that a small-sized and light-weight fluid machine is achieved with a long life. In addition, the section area of the fluid path of the center plate is sufficiently ensured, so that the performance deterioration caused by a pressure loss in a high flow-rate operation is prevented.

BRIEF EXPLANATION OF THE DRAWINGS

[FIG. 1] FIG. 1 is longitudinal section view of a scroll-type compressor according to an embodiment of the present invention.

[FIG. 2] FIG. 2 is a partial enlarged longitudinal section view where a neighborhood of part A of FIG. 1 has been enlarged.

EMBODIMENTS FOR CARRYING OUT THE INVENTION

Hereinafter, desirable embodiments will be explained as referring to figures.

FIG. 1 is a longitudinal section view of a scroll-type compressor according to an embodiment of the present invention. Compressor 1 comprises first housing 4 to house fixed scroll 2 and movable scroll 3, crank mechanism 6 to convert the rotation of main shaft 5 to the swing of movable scroll 3, center plate 8 provided with rotation preventing mechanism 7 to prevent movable scroll 3 from rotating and second housing 10 to house electric motor 9, wherein electric motor 9 and compressor 1 are disposed in the same axis. Cylindrical bearing holding section 12 to hold bearing 11 of main shaft 5 is attached to a surface at electric motor 9 side of center plate 8. A plurality of radially formed ribs (not shown) are provided at the outer side from bearing holding section 12 in a radial direction. A plurality of radial recessed portions 13 extending axially along main shaft 5 are formed to have inner surfaces which extend as tapering toward the inside of second housing 10.

On the other hand, a surface of first housing 4 side of center plate 8 is provided with radial recessed portion 14 which extends in a direction perpendicular to main shaft 5 and which is formed to be a ring-shaped recess extending over a whole circumference of center plate 8. The inner surface of radial recessed portion 14 is formed in a tapered shape extending in parallel with main shaft 5 from the inside of first housing 4 toward the inside of second housing 10 (electric motor 9 side).

Such formed radial recessed portion 14 and a plurality of axial recessed portions 13 communicate each other, so that a fluid path through which refrigerant gas to be compressed flows is formed. The refrigerant gas sucked from suction port 15 is delivered through a gap of electric motor 9 to a front side of center plate 8, and then, is taken into movable scroll 3 mainly via axial recessed portion 13 and radial recessed portion 14. After it is compressed by a compression mechanism made of movable scroll 3 and fixed scroll 2, it is discharged from discharge port 18 via discharge hole 16 and discharge chamber 17. The refrigeration circuit of compressor 1 is constructed to make such a path. Because refrigerant gas, which conventionally used to flow in a gap of bearing 11 or a gap at the outer periphery side of bearing holding section 12, comes to be able to flow inside a fluid path made of the radial recessed portion 14 and axial recessed portion 13 so as to ensure the section area of the refrigerant gas flow path, the pressure loss can be reduced in a high flow-rate operation.

FIG. 2 is a partial enlarged longitudinal section view where a neighborhood of part A of FIG. 1 has been enlarged. Desirable size and shape of axial recessed portion 13 and radial recessed portion 14 will be explained as referring to FIG. 2 as follows.

It is preferable that axial length a in an overlap region of axial recessed portion 13 and radial recessed portion 14 is 2-9 mm. The longer length a is, the more pressure loss is reduced. However excessively long length a would weaken the strength of center plate 9.

It is preferable that angle b, which is wedged between an end surface at movable scroll 3 side of center plate 9 and a tapered inner surface of radial recessed portion 14, is 20-60 degrees. Angle b within this range makes it easy to process radial recessed portion 14.

It is preferable that angle c (e) between the tapered inner surface of axial recessed portion 13 and the axial direction is 1-4 degrees. Angle c within this range makes it possible to improve fluidity of refrigerant gas which flows into axial recessed portion 13 from the inside of second housing 10 as well as to simplify processing radial recessed portion 14.

It is preferable that radial depth d of radial recessed portion 14 is 3-9 mm. Depth d within this range makes it possible to improve fluidity of refrigerant gas which flows from axial recessed portion 13 via radial recessed portion 14 into the inside of first housing 4 as well as to simplify processing radial recessed portion 14.

INDUSTRIAL APPLICATIONS OF THE INVENTION

A scroll-type fluid machine according to the present invention is suitably used as a compressor for vehicles, etc., which is required to have a small side and light weight.

EXPLANATION OF SYMBOLS

1: compressor

2: fixed scroll

3: movable scroll

4: first housing

5: main shaft

6: crank mechanism

7: rotation preventing mechanism

8: center plate

9: electric motor

10: second housing

11: bearing

12: bearing holding section

13: axial recessed portion

14: radial recessed portion

15: suction port

16: discharge hole

17: discharge chamber

18: discharge port

a: axial length in overlap region of axial recessed portion and radial recessed portion

b: angle between end surface at movable scroll side and tapered inner surface of radial recessed portion

c, e: angle between tapered inner surface of axial recessed portion and axial direction

d: radial depth of radial recessed portion 

1. A scroll-type fluid machine comprising: a first housing which houses a scroll mechanism made of a fixed scroll and a movable scroll; a second housing which houses an electric motor to rotate a main shaft; and a center plate, which is interposed between said housings, which has a motion conversion mechanism to convert a rotation motion of said main shaft to a swing motion of said movable scroll, which is provided with a rotation preventing mechanism for said movable scroll, and which holds a bearing to hold said main shaft, and a fluid path which communicates an inside of said second housing and an inside of said first housing through an installation part of said center plate, wherein at least a part of said fluid path is formed by connecting an axial recessed portion and a radial recessed portion, which are formed in said center plate, said axial recessed portion facing said inside of said second housing and extending in an axial direction, said radial recessed portion being located closer to said first housing than said bearing and extending in a radial direction.
 2. The scroll-type fluid machine according to claim 1, wherein a plurality of said axial recessed portions are formed along a circumferential direction.
 3. The scroll-type fluid machine according to claim 1, wherein a part of an inner surface of said axial recessed portion is formed to be a surface extending in a shape tapered toward said inside of said second housing.
 4. The scroll-type fluid machine according to claim 1, wherein said radial recessed portion is formed to be a ring-shaped recess extending in a circumferential direction.
 5. The scroll-type fluid machine according to claim 1, wherein a part of an inner surface of said radial recessed portion is formed to be a surface extending in a shape tapered toward said inside of said second housing from said inside of said first housing.
 6. The scroll-type fluid machine according to claim 1, wherein said axial recessed portion is provided at a time of producing a material for said center plate.
 7. The scroll-type fluid machine according to claim 6, wherein said material for said center plate is produced by casting and said axial recessed portion is formed with a die.
 8. The scroll-type fluid machine according to claim 1, wherein said radial recessed portion is formed by machining.
 9. The scroll-type fluid machine according to claim 1, wherein said center plate is formed integrally with either said first housing or said second housing. 